A plethora of changes occur in the body to accommodate for the growth of another living being. Many of these changes are completely normal and are necessary for a healthy pregnancy; however, some abnormal symptoms may warrant concern. Below lists normal cardiac changes during pregnancy and symptoms that are abnormal. If a woman experiences any of these abnormal symptoms during pregnancy, it is important to consult with her obstetrician and cardiologist.

Normal changes during pregnancy:

  • Blood volume increases by 40-50%
    • When plasma volume increases quicker than red blood cell mass, anemia occurs
  • Cardiac output (CO) rises 30-50% above baseline and is highest at the end of the 2nd trimester
  • Stroke volume increases in the 1st & 2nd trimesters and decreases in the 3rd trimester when the fetus compresses the inferior vena cava (IVC)
  • Hypercoagulation (increased ability for blood to clot)
  • Heart rate increases by 10-15 bpm
  • Decrease in blood pressure by 10 mmHg
  • Many women have audible systolic murmurs due to changes in blood flow

Hypercoagulation during pregnancy

  • Pregnancy induces hypercoagulation, which is an increased ability of blood to clot. This is due to an increase in clotting factors, as well as venous stasis (slowing of blood flow) which is caused by the fetus compressing the IVC. This hypercoagulation is most likely an evolutionary mechanism to protect against maternal hemorrhage. Studies have shown that due to this hypercoagulation though, pregnant women are three to four times more likely to have arterial thromboembolism (blood clot) and four to five times more likely to have venous thromboembolism as compared with women who are not pregnant.

Normal changes during pregnancy can mimic signs and symptoms of heart disease, so it is important to know the difference between what is normal and abnormal in terms of cardiovascular function during pregnancy.

Abnormal signs and symptoms include:

      • Exertional chest pain
      • Paroxysmal nocturnal dyspnea (attacks of severe shortness of breath and coughing during the night)
      • Orthopnea (shortness of breath while lying flat)
      • Sustained atrial or ventricular arrhythmias
      • Pulmonary edema
      • Severe obstructive systolic murmurs
      • Diastolic murmurs
      • An S4 gallop.
    • Some general abnormal symptoms are trouble breathing (especially at night or when not active), weakness, fatigue, dizziness or fainting, palpitations, and cyanosis (blue discoloration of skin and nails).



  1. Naderi, S, Raymond R. Pregnancy and heart disease. Dis manag. 2014. http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/cardiology/pregnancy-and-heart-disease/.

By: Stephanie Kramer